The invention relates to an inlet system for a two-cycle internal combustion engine with at least one cylinder around which scavenging air passages are arranged in at least two inlet rows disposed in at least two separate air admission planes, wherein the admission of the scavenging air is controlled by the piston reciprocating in the cylinder.
DE 28 54 346 C2 discloses such an air inlet system for a two-cycle engine with uniflow scavenging. The engine comprises an operating cylinder with a cylinder working surface which includes scavenging slots distributed circumferentially around the cylinder in two inlet rows disposed adjacent one another. Opening of the scavenging air slots in the cylinder operating surface and admission of scavenging air to the cylinder is controlled by a piston reciprocating in the cylinder. The engine includes an auxiliary blower separate from the operating cylinder-piston set by which fresh air can be admitted to the cylinder via two rows of inlet scavenging slots.
The similar EP 02 04 687 A2 discloses a two-cycle engine with a cylinder having a cylinder wall in which circumferentially distributed converging slots are arranged. The engine further includes a control arrangement which influences the spin of the fresh charge air entering the cylinder through the inlet slots. The fresh air charge stream is divided into two partial streams such that the fresh air charge in the charging space surrounding the cylinder obtains, via the control arrangement, a controllable pre-spin depending, preferably, on engine speed and engine load.
For further, general, background information reference is made to the publications DE-PS 10 15 267, DE 29 09 591 C2, DE 35 10 770 C2 and DE 41 33 138 A1.
It is the object of the present invention to provide an inlet system for a two-cycle engine in such a way that, when the scavenging slots are open, spin and volumetric flow of the fresh air admitted to the cylinder can be controlled such that fuel consumption and emissions of the engine are reduced.